The invention relates to superconductive tunnel elements, tunnel stacks produced therefrom and use thereof.
EP 0 513 557 A2 discloses superconductive tunnel elements, tunnel stacks produced therefrom and uses based thereon. These tunnel elements have the structure superconductor, tunnel barrier, superconductor; there is in each instance an insulated superconductive control layer within the two superconductors. This arrangement gives a uniform and homogeneous flux of the current-induced magnetic fields of the control layers through the superconductors, so that the energy gap of the superconductors can be controlled very accurately. Moreover, the symmetrical structure of this element permits a nonproblematic integration of a plurality of elements to form a tunnel stack, in that superconductors and barriers are alternately disposed successively one on another. However, a disadvantage of this device is that a large number of individual layers are present. Thus, one superconductor already consists of five individual layers (one control layer, two insulating layers for insulating the control layer and two superconductive layers). Accordingly, the production of these tunnel cells is very costly and expensive.
The object of the invention is accordingly to specify a tunnel element which can be produced substantially more simply and cheaply with hardly any impairment of controllability as compared with EP 0 513 557 A2.
This object is achieved by a tunnel including superconductors, barriers and insulators. The tunnel element has the following layer structure: superconductor (S1), insulator (I), superconductor (S2), barrier (B), superconductor (S3), insulator (I), and superconductor (S4). Advantageously designed tunnel elements are provided. Advantageous possible circuits of the tunnel elements are specified. Advantegous tunnel stacks produced from the novel tunnel elements are also specified. Uses of the tunnel elements are also provided.
In the text which follows, the invention is explained in greater detail with reference to illustrative embodiments of tunnel elements, their circuits and of tunnel stacks and their uses.